Improving Germination and Emergence In Low Phytate Soybeans.

Phytate is the primary compound in which seeds store phosphorus and is indigestible to monogastric livestock.  One approach to reducing this compound in feed seeds, including soy, is mutations that condition the low phytate (LP) trait.  The two sources of the LP trait in soybean are mutations in the MIPS1 gene characterized in three mutant lines, and mutations in both Lpa1 and Lpa2, present in the line CX1834.  The LP trait reduces germination and emergence of seeds and seedlings in germplasm derived from both sources.  We hypothesize that germination and emergence (G&E) in LP soybeans can be genetically improved through careful selection of parents and a calculated approach to early-generation selection.  Our objectives were to collect preliminary data on parent selection and early-generation breeding methods for LP soybean segregating populations.  In 2010 we planted F₂-derived lines and populations of various pedigrees including both LP sources and measured G&E and seedling diseases to search for evidence of genetically controlled differential germination and emergence.